Ceramic matrix composites (CMCs) are a new type of material that can integrate the advantages of multiple materials. They are often used in jet engines, gas turbines, and nickel superalloy tools, so they have long been favored by scientists. Among them, aluminum oxide (Al2O3) and tungsten carbide (WC) are a pair of very interesting combinations. The former is hard and chemically inert, and the latter can be used as superhard materials. Unfortunately, no one has yet Al2O3-WCCMC with satisfactory performance can be prepared.
Recently, a team of scientists from Japan led by scientists from Nagoya University and in cooperation with NGK Spark Plug Co., Ltd. conducted a study. They added a small amount of zirconium dioxide (ZrO2) in the process of manufacturing Al2O3-WC-CMC. , And finally produced "super hard" Al2O3-WC-CMC with a bending strength greater than 2 gigapascals. As the lead researchers Dr. Nishi and Dr. Matsunaga said: "This is the highest level in history in this field."
When the researchers used atomic-resolved scanning transmission electron microscopy to study the structure of its superhard ZrO2-enhanced Al2O3-WC-cmc, they found that the Zr atoms are located in the thin layer between the Al2O3 and the WC sheet. Dr. Nishi and Dr. Matsunaga pointed out that “the interface between Al2O3 and WC is generally a weak point in the structure of composite materials.” Later, researchers used a technique in the field of mathematical physics called density functional theory to simulate the zirconium atom. Effect, it is found that these zirconium atoms in the interface layer enhance the stability of CMC.
Commenting on its potential applications, Dr. Matsunaga said: “The material we have developed can be used as a superhard material for metal processing equipment, cutting hard metal parts used in airplanes and automobiles.” In fact, they noticed NGK Spark Plug Co., Ltd. Of engineers have begun to use these materials in commercial cutting tools.
